Surgery for the Unstable Shoulder
In general, shoulder surgery can be done in two fundamentally different ways: using closed surgical techniques (arthroscopy or "keyhole" surgery) or using open surgical techniques. Arthroscopy is a microsurgical technique whereby the surgeon can use an endoscope to look through a small hole into a joint. The endoscope is an instrument, the size of a pen, which essentially consists of a tube containing a light and/or a miniature video camera, which transmits an image of the joint interior to the examiner's eye via a television monitor. (Fig 8a)
Traumatic Unidirectional Instability
Bankart Lesion Repair
Shoulder instability resulting from trauma usually involves a Bankart lesion; i.e., detachment of the anterior part of the labrum from the rim of the glenohumeral cavity (as shown on Fig. 8b). The most recent and successful surgical procedure for unidirectional shoulder instability is an arthroscopic variation of open Bankart repair. In the arthroscopic procedure, the detached part of the labrum and the associated ligaments are reattached to bone along the rim of the glenohumeral cavity through a small "keyhole" incision.
This is done with little disruption to the other shoulder structures; e.g., without the need to detach and reattach the overlying subscapularis muscle. Because it is less invasive than open surgery, the arthroscopic procedure tends to preserve the range of movement for external rotation, and to reduce the risk of osteoarthritis. However, 7%-17% of shoulders redislocate if they are repaired using arthroscopic anterior shoulder stabilisation whereas only 5% of unstable shoulders redislocate if repaired using open surgical procedures (See Table, Fig 8c).
Arthroscopic techniques for reattaching the labrum to the glenohumeral cavity may use:
- suture anchors (Fig. 8d); or
- biodegradable tacks (eg. Suretac, Acufex Microsurgical Inc, Norwood, MA.) (Fig. 8e).
By way of comparison, an open Bankart repair consists of detaching and later reattaching the humeral insertion of the subscapularis tendon, and also reattaching the labrum to the anterior glenoid cavity with sutures through the bone or with suture anchors. With the open technique, the shoulder loses on the average 12° of external rotation following anterior stabilisation, probably because the subscapularis tendon is shortened after the detachment/reattachment process.
SLAP Lesion Repair
SLAP stands for "Superior Labrum Anterior Posterior". SLAP lesions occur less frequently than Bankart lesions. In SLAP lesions, the labrum detaches from its usual location along the top margin of the shoulder cavity. This detachment is associated with clicking sounds, locking of the shoulder, and/or a feeling that the shoulder is "not right" but it is rarely associated with frank shoulder instability. Best diagnosed by arthroscopy, the labrum can be reattached using an arthroscopically delivered biodegradable tac or suture anchor.
Rotator Interval Closure
Normally there is a small gap between the subscapularis and supraspinatus muscles. In a preliminary study of patients with subluxation, some success was achieved in stabilising the shoulder by closing this gap.
Multidirectional Instability Repair
Anterior Capsular Shift:
The most commonly performed and the most successfully reported surgical procedure for tightening the capsule is the anterior capsular shift. This can be used for patients with a large amount of anterior instability but it is particularly useful for patients with multidirectional shoulder instability. For this, slack in the capsule is reduced by making a "T-shaped" cut through the capsule, overlapping the anterior and inferior margins of the cut, and then stitching the overlapped part of the capsule (Fig. 8f).
Several studies have shown that heat applied to a loose capsule can cause local shrinkage and, therefore, tightening of the capsule. Heating an area of the shoulder capsule to 65-71° resulted in a shortening of capsule collagen fibres and a 15-40% reduction in capsule size . Arthroscopic devices have been designed to deliver heat to the shoulder capsule so the loose capsule can be shrunk through a small incision. This procedure is still being developed and improved.
Warning: Do not attempt any procedures described on this website unless you are fully trained. Otherwise, serious injury may occur. Always seek expert advice and help.